Known envelope flaps often have a moisture activated adhesive, but could also include a removable barrier over the adhesive (so called peal and stick), or any other included adhesive. Prior to the traditional adhesive strip, flaps were sealed with an external binding connected to both the flap and adjacent side to bind the flap closed. This binding could be melted wax or something similar. An affixable seal (e.g. a foil piece with adhesive included on one side), and/or a sticker type item has also been used to seal (or double seal in conjunction with included flap adhesive) envelope flaps. U.S. Pat. No. 2,367,440 describes a self-sealing paper envelope. Also, U.S. Pat. No. 5,429,576 describes a reusable adhesive envelope having a pressure sensitive adhesive, which is initially covered by a release liner. Upon removing the release liner the adhesive on the flap may be secured to the protective strip to close the flap, which may be opened and closed numerous times.
Traditional envelopes, particularly postal mailing envelopes, are configured to have a ship to and return to address printed on the envelope or affixed to the envelope (e.g., through an adhesive or a receiving window). Return addresses are often printed on pre-printed affixable labels, since unlike the ship to address, the return address text does not often change. By rule, these are typically affixed in a particular area (e.g., the upper left corner of the front side or center top of the reverse side).
Users of envelopes will sometimes double seal an envelope to ensure it does not open during transit, or otherwise increase the closure seal. A deficiency of the most common included adhesive, i.e., moisture activated adhesives, is that a heavy humidity, heat, or other environmental condition can weaken or even release the closure seal, thereby opening the envelope during transit. A user may apply some tape or a sticker across the flap and adjacent side in order to deter this deficiency of just the flap adhesive alone. U.S. Pat. No. 913,987 describes an envelope where projecting tongues adapted to fold over the sealing flap after the latter is folded and sealed, and thus firmly secure the sealing flap and prevent it from being opened. U.S. Pat. No. 3,702,171 describes an envelope with superimposed strips aligned to be partially lifted and placed back down on the flap to seal the envelope.
It is desirable to provide an improved sealing arrangement.